The present invention relates to grinding spindle holders adapted to accommodate two or more grinding spindles, and mounted on, or adapted for attachment to a feed slide guided for movement on a working table of a grinding machine, said holder having a stationary base part mounted on the slide, or adapted for attachment thereto and a moveable spindle-receiving part which can be stepped rotationally about an axis parallel with the spindle axes, to move the spindles consecutively into a grinding position for engagement with a workpiece in one and the same chuck position.
Various kinds of multi-spindle, rotatable holders of the kind driven by a common drive means in the form of a belt transmission which drives the relevant spindle located in a working position are known to the art, for example from U.S. Pat. Nos. 925,867; 1,051,483; and 2,300,481; and from the French Patent Specification No. 611 327, all of which describe and illustrate older types of arrangement.
These known older spindle arrangements, however, are unable to fulfil the accuracy requirements of today, among other things because the spindles cannot be adjusted in their working positions which sufficient precision.
In more recent grinding machines, each spindle is normally driven individually by a separate drive motor, which renders the use of the arrangement to produce the stepped rotary movement achieved by the older arrangements described in the aforesaid patent specifications impossible.